ELECTRON-BEAM-DEPOSITED MO SI AND MO(X)SI(Y)/SI MULTILAYER X-RAY MIRRORS AND GRATINGS/

For the wavelength region above the Si-L edge normal incidence, soft x -ray mirrors are produced with peak reflectivities close to 60%. The m ultilayer systems consist of molybdenum and silicon and are fabricated by electron beam evaporation in ultrahigh vacuum. A smoothing of the boundaries, and thereby a drastic enhancement of the reflectivity, is obtained by thermal treatment of the multilayer systems during growth. The thermal stability of the multilayer stacks could be improved cons iderably up to 850-degrees-C by mixing Mo and Si in the absorber layer s and producing thus Mo(x)Si(y)/Si multilayers with x and y denoting t he amounts of Mo and Si in the absorber layer, respectively. First att empts are reported to produce mirrors with a bilayer thickness of 2.6 nm. An improvement in the quality of these interfaces can be obtained by bombardment with Ar+ ions. We report on normal incidence reflectivi ty measurements of the mirrors with synchrotron radiation and finally on the normal incidence diffraction efficiencies of a Mo/Si multilayer coated grating, for which values of 5.5% are achieved for the + 1'st and - 1'st diffraction orders.